Home›Maneuver Tracker›Close Approaches›COSMOS 2503 ⟷ OBJECT J
HighProximity
RussiaCOSMOS 2503NORAD 40420 · launched Feb 2015Military payload
2.08kmPredicted miss distance
TBDOBJECT JNORAD 42833 · launched Jul 2017Payload
Final forecastFinal forecast, made 12 min before the pass.
After the passBest estimate, from the orbit data published nearest its time: 2.23 km at 3 Nov 03:21 UTC.
Closest approach3 Nov 202603:21 UTC
Relative speed11.53 km/sat the closest approach
Altitude531 kmlow Earth orbit
Last confirmed3 Nov03:09 UTC · final forecast
Track COSMOS 2503Track OBJECT JAll approaches
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RU COSMOS 2503 and TBD OBJECT J were predicted to reach a closest approach of 2.08 km at 2026-11-03 03:21 UTC, at a relative speed of 11.53 km/s. Final forecast, made 12 min before the pass. Best estimate after the pass, from the orbit data published nearest its time: 2.23 km at 3 Nov 03:21 UTC. Miss distance and time of closest approach are computed by propagating the latest published orbital elements for both objects, and each pass is re-checked every 20 minutes as new element sets are published. See the Satellite Maneuver Tracker for the live picture and space situational awareness for context.

Why it mattersBoth objects are catalogued as payloads. Screening continues as new element sets arrive; operators act on their own conjunction data.

The Two Objects

Dossiers from the satellite directory
COSMOS 2503Payload
NORAD 40420
CountryCIS
Launched2015-02-27
OrbitLEO · 534 × 557 km
COSPAR2015-009A
Maneuver capableUnknown
Profile →Globe →
OBJECT JPayload
NORAD 42833
CountryTBD
Launched2017-07-14
OrbitLEO · 532 × 540 km
COSPAR2017-042J
Maneuver capableUnknown
Profile →Globe →

Where This Happens

Altitude context
DEBRIS BELT 700–1000 KM2006001,0001,5002,000 kmTHIS PASS · 531 KMISS 420Starlink 550

At 531 km this pass sits in low Earth orbit. Objects here stay up for decades: there is too little atmospheric drag to clean the band naturally. Why crowded bands matter →

History Between This Pair

1 predicted pass under 10 km
Pair history · COSMOS 2503 ⟷ OBJECT J
2026-11-03 03:212.08 km Final forecast11.53 km/s531 kmShown above

Repeat encounters are common for objects in near-intersecting orbital planes. Each pass is re-screened as fresh element sets arrive; "Final forecast" means the screening still predicted it within 45 minutes of its time, "Not re-confirmed" means later screening stopped finding it.

Forecast Record

Every figure published for the pass shown above, newest first. Nothing is overwritten: a withdrawn forecast keeps its figure, with the newer check beside it, and the best estimate after the pass is a row of its own.
Computed · figure · predicted time · orbit data · by
6 Nov 07:55 UTC2.23 km Best estimate3 Nov 03:21 UTC3 Nov 09:17 UTCBest estimate
2 Nov 21:35 UTC2.08 km Forecast3 Nov 03:21 UTC2 Nov 11:04 UTCRe-check
2 Nov 12:15 UTC2.82 km Forecast3 Nov 03:21 UTC1 Nov 22:19 UTCRe-check
2 Nov 11:55 UTC8.53 km Forecast3 Nov 03:21 UTC1 Nov 22:19 UTCScreen

These Objects Elsewhere

Other screened approaches · 7 days
2.02 km11-05 03:13 UTC
COSMOS 2503HYDROGNSS-1
4.78 km11-04 23:51 UTC
COSMOS 2503OPTICUBE 04
5.07 km11-01 04:22 UTC
COSMOS 2503CZ-6A DEB

How These Numbers Are Computed

Miss distance and TCA come from propagating the latest published orbital elements for both objects and searching for the minimum separation over the screening window. Element sets carry kilometre-scale uncertainty, so figures here describe a close pass, not a collision prediction; a change in either object's published elements re-computes the pass automatically. What is a conjunction? → How conjunction assessment works →